Trailers used to haul loose materials such as dirt, sand, gravel, or grain commonly have beds or tubs that have an open top. Therefore, if the trailer bed is not covered as the trailer is pulled over the road, the loose contents may be blown and scattered out of the open top of the trailer bed. Additionally, the contents of the trailer bed may be compromised by rain, or other contaminants. Accordingly, it is known to deploy tarps across the open top space of the trailer beds to cover the contents of the trailer beds.
Several mechanisms have been devised for deploying the tarps across the trailer bed. Many of these devices include radial arms that are rotatably mounted at the front and rear of the tub and have a roll of tarp disposed between them. As the radial arms rotate in one direction across the truck bed, the roll of tarp between the arms is unrolled to cover the contents of the truck bed. When the arms are rotated back in the opposite direction, the tarp is taken back up upon the roll to uncover the trailer bed. Examples of such devices may be seen in Searfoss, U.S. Pat. No. 6,206,449 and in Michel, U.S. Pat. No. 5,002,328.
Rear dump trailers are able to dump their contents by raising the forward end of the tub and releasing a rear door or flap to permit the contents of the tub to slide out under the bottom of the door or flap. Typically the radial arm of the tarp deploying apparatus will be mounted to the rear door or flap. Bremer, U.S. Pat. No. 8,910,996, the entire contents of which are hereby incorporated by reference, shows and describes such a structure.
The rear flap can be subjected to significant stresses during dumping operations as the contents of the of the trailer slide down the trailer and bang into the flap. As a result, the rear flap will occasionally be dislodged from the trailer. In instances where there is no tarp deploying apparatus attached to the rear flap this is an inconvenience, but is easily fixed by simply reattaching the flap. However, for the systems that have the radial arms attached to the rear flap the dislodging of the flap often results in damage to the tarp deploying apparatus. The damage can take the form of bent radial arms, deformed tarp rollers, and ripped tarps. The damage to the tarp deploying system is expensive to repair. Even worse, it can result in lengthy down time for the trailer while replacement parts are being acquired and repairs are being made.
Accordingly, there is a need for an improved tarp deploying apparatus for rear dump trailers that reduces the risk of significant and expensive damage to the tarp deploying apparatus when the rear door or flap becomes dislodged from the trailer.